A. Field of the Invention
This invention relates to the field of telecommunications and more specifically to a method and apparatus for communicating packet fragments over a symmetrical interface with reversed asymmetrical links.
B. Description of Related Art and Advantages of the Invention
Various types of asymmetric communication techniques are utilized for data transmission. These types of communication techniques include Asymmetric Digital Subscriber Line (ADSL), Cable Modems (High Frequency Cable), and X2 Technology(trademark) from 3Com Corporation. These techniques utilize an interface that communicates information asymmetrically. Information is communicated asymmetrically since the interface has a disparity in transmission rates. In other words, an asymmetric device has a greater rate of up-link data transmission than down-link data transmission or visa-versa. For example, in the case of ADSL, the data transmission rate or bandwidth may be 640 kilobytes in one direction (either the device""s up-link transmission rate or down-link receiving rate) and 4 megabytes in the opposite direction. For ADSL, therefore, the difference between the up-link and the down-link rates or the asymmetric difference represents approximately a six fold difference in bandwidth.
Asymmetric interfaces may be supplied in two types: either client access based or server access based. The client access based interface has a greater down-link receiving rate than its corresponding up-link transmitting rate. The user access based interface is ideal in communication applications requiring fast down-link rates (e.g., a personal computer accessing the world-wide-web). Conversely, a server access based interface has a greater up-link transmission rate than its corresponding down-link receiving rate. The server access based interface is ideal in communication applications requiring fast link rates (e.g., a World-Wide-Web server).
One problem associated with such asymmetric interfaces is the asymmetric difference. A data transmitting or receiving device such as a personal computer or server coupled to an asymmetric interface will not be able to up-link and down-link with the same amount of bandwidth. Therefore, the data transmission device, such as a computer, a World Wide Web or a network server will have limitations on its rate of transmission vis-à-vis its down-linking or up-linking speeds.
The present invention relates to a method and apparatus for communicating packet fragments over a symmetrical interface with reversed asymmetrical links. In a first aspect of the invention, a method for communicating packet fragments over a symmetrical interface with reversed asymmetrical links comprises the steps of coupling a first asymmetric interface to a computing device. The first asymmetric interface has an up-link transmission rate that is greater than its down-link receiving rate. The difference between the up-link rate and the down-link rate defining a first asymmetric difference. A second asymmetric interface is coupled to the computing device. The second asymmetric interface having a down-link receiving rate and an up-link transmission rate. The down-link rate is greater than the up-link rate and the difference between the down-link rate and the up-link rate of the second asymmetric interface defines a second asymmetric difference. The second asymmetric difference being substantially equal to the first asymmetric difference.
In another aspect of the invention, a method for communicating packet fragments over a multiple parallel asymmetric interface comprises the steps of coupling a first linking interface to a first computing device. The first linking interface transmits packet fragments from the first computing device at an up-link data transmission rate and receives packet fragments to the first computing device at a down-link data receiving rate. The up-link rate is greater than the down-link rate. The difference between the up-link rate and the down-link rate of the first linking interface defines a first linking difference. A second linking interface is coupled to the first computing device. The second linking interface receives packet fragments at a down-link data receiving rate and transmits packet fragments at an up-link data transmission rate. The down-link rate is greater than the up-link rate. The difference between the down-link rate and the up-link rate of the second linking interface defines a second linking difference. The second linking difference being generally equivalent to the first linking difference. A third interface is coupled to a second computing device. Packet fragments are transmitted from the first computing device. Up-linked packet fragments are transported to the third interface such that the third interface receives and down-links the transported packet fragments to the second computing device.
In another aspect of the invention, a multiple parallel asymmetric interface with reversed asymmetric links comprises a first asymmetric interface having an up-link data transmission rate and a down-link data receiving rate. The down-link rate is less than the up-link rate wherein a difference between the up-link rate and the down-link rate defines a first asymmetric difference. A second asymmetric interface has a down-link data receiving rate and an up-link data transmission rate. The up-link rate is less than the down-link rate wherein a difference between the down-link rate and the up-link rate defines a second asymmetric difference. The second asymmetric difference is generally equivalent to the first asymmetric difference.
In another aspect of the invention, an apparatus for symmetrically linking packet fragments comprises a first asymmetric linking interface having a plurality of first receiving channels for receiving packet fragments and a plurality of first transmitting channels for transmitting packet fragments. A second asymmetric linking interface has a plurality of second transmitting channels for transmitting packet fragments and a plurality of second receiving channels for receiving packet fragments. The plurality of first receiving channels and the plurality of second receiving channels define a receiving link having a down-link receiving rate. The plurality of first transmitting channels and the plurality of second transmitting channels define an up-link having an up-link transmission rate. The up-link rate generally equivalent to the down-link rate.
In still another aspect of the invention, a multiple parallel asymmetric interface with reversed asymmetric links comprises a computing device. A first asymmetric linking interface has a plurality of first receiving channels for receiving packet fragments to the computing device and a plurality of first transmitting channels for transmitting packet fragments from the computing device. A second asymmetric linking interface has a plurality of second transmitting channels for transmitting packet fragments from the computing device and a plurality of second receiving channels for receiving packet fragments to the computing device. The plurality of first receiving channels and the plurality of second receiving channels define a down-link having a down-link receiving rate. The plurality of first transmitting channels and the plurality of first transmitting channels defme an up-link having an up-link transmission rate, the up-link rate generally equivalent to the down-link rate.
These and many other features and advantages of the invention will become more apparent from the following detailed description of the preferred embodiments of the invention.